-If BY is used (see below), the SORT keyword must be specified after a
-FILE if that input file is not already sorted on the BY variables.
-When SORT is specified, PSPP sorts the input file's data on the BY
-variables before it applies it to the command. When SORT is used, BY
-is required. SORT is a PSPP extension.
+If @subcmd{BY} is used (see below), the @subcmd{SORT} keyword must be specified after a
+@subcmd{FILE} if that input file is not already sorted on the @subcmd{BY} variables.
+When @subcmd{SORT} is specified, @pspp{} sorts the input file's data on the @subcmd{BY}
+variables before it applies it to the command. When @subcmd{SORT} is used, @subcmd{BY}
+is required. @subcmd{SORT} is a @pspp{} extension.